This program brings together a team of collaborators with extensive experience in engineering, manufacture, testing, and clinical application of miniaturized axial flow blood pump technology. We will rapidly implement dramatic miniaturization of the Jarik 2000 hear and apply it to pediatric patients. Within three years we will complete development and testing of a 35 gram 10cc blood pump designed for long term support in children of approximately 15-25 Kg. In years four and five we wil develop a still smaller 10 gram 3cc blood pump for infants and small children of approximately 3- 15 Kg. body weight. The Jarvik 2000 heart is the most successful of five LVAD systems funded by the NIH IVAS contracts beginning in 1995. That five year program was successfully completed in 1999. Our contract performance accomplished its major goals and received the highest scores possible in all categories in its NIH final evaluation. Over the past three years the Jarik 2000 has been implanted in 55 patients in the United States and Europe. The first bridge to transplant patient was operated at the Texas Heart Institute, was supported for 78 days, was transplanted successfully, and is well three years later. The first "lifetime use" recipient has been supported for three years and remains in excellent health. Many other patients are doing well years after receiving the device. There have been no bearing failures in any patient. The few device related infections that occurred were all successfully treated. Some thrombus, thromboembolism, and hemolysis has occurred, but at an acceptably low incidence. Improvements in surgical technique, patient selection, and patient management will reduce the rate of these complications. We ultimately expect >10 year survivals with the Jarvik 2000 in both LVAD and BVAD configurations. In the mid 90's, we developed a prototype pediatric model of the Jarvik 2000 and animal tested it for up to four months at Oxford, England. We postponed further work on it because we did not have the resources to pursue both an adult and child model. Since then, we have made many important design and manufacturing advances in the adult model that are directly applicable to the child and infant sizes. The pediatric devices we propose will not be exact scale down versions and will require new blade design for the lower flow and pressure requirements of children and infants. We will utilize advanced CFD methods together with flow visualization and Ex Vivo hemolysis testing to achieve acceptably low blood damage in these very small pumps. In the initial pediatric patients (during year 4) we will use the analog control system previously qualified for adults. By year 5 we will complete a much smaller microprocessor based programmable control system with human engineering to allow it to be worn by children with adult supervision. The child and infant models will be both small and versatile. They will be implantable in any of the four chambers of the normal heart, and also are expected to be applicable by various creative surgical techniques to deal with chronic mechanical left, right, or biventricular support in a wide range of congenital anomalies. Anatomic studies as well as a computerized MR based fitting model are an important part of this program. Jarvik Heart, Inc. is an ISO 9001 registered company and the University of Maryland animal lab is GLP qualified. The clinical teams at our participating centers have extensive VAD and transplant experience. Jarvik Heart recognizes that the limited available funds would not be sufficient to complete a program of this scope for many of the companies and academic institutions working in this field. We are small, focused, efficient, and willing to accept considerable cost sharing to complete this program. The clinical institutions working with the adult Jarvik 2000 have demonstrated their ability to find sufficient resources to conduct clinical cases without outside funding, and will succeed for the children.